feat: add an install script to download the golang test-server.

[wanlin31]

This PR introduces an install.py script to automate the download, verification, and installation of the test-server binary from its GitHub Releases page.

Tested:

python3 -m venv ~/env
source ~/env/bin/activate

python install.py

Output:

Downloading test-server_Linux_x86_64.tar.gz from https://github.com/google/test-server/releases/download/v0.2.6/test-server_Linux_x86_64.tar.gz...
Download complete.
Verifying checksum...
Checksum verified successfully.
Extracting binary from /usr/local/google/home/wanlindu/test-server/sdks/python/bin/test-server_Linux_x86_64.tar.gz to /usr/local/google/home/wanlindu/test-server/sdks/python/bin...
/usr/local/google/home/wanlindu/test-server/sdks/python/install.py:117: DeprecationWarning: Python 3.14 will, by default, filter extracted tar archives and reject files or modify their metadata. Use the filter argument to control this behavior.
  tar_ref.extractall(BIN_DIR)
Extraction complete.
Cleaned up /usr/local/google/home/wanlindu/test-server/sdks/python/bin/test-server_Linux_x86_64.tar.gz.
Set executable permission for /usr/local/google/home/wanlindu/test-server/sdks/python/bin/test-server
test-server binary is ready at /usr/local/google/home/wanlindu/test-server/sdks/python/bin/test-server

The try to run the binary:

./usr/local/google/home/wanlindu/test-server/sdks/python/bin/test-server

Output

Test-server allows recording requests and responses made to
a server and then replay the recorded sequenced as part of text fixtures.

Usage:
  test-server [command]

Available Commands:
  completion  Generate the autocompletion script for the specified shell
  help        Help about any command
  record      Run test-server in record mode
  replay      Replay recorded HTTP responses

Flags:
      --config string   config file (default is ./test-server.yaml)
  -h, --help            help for test-server

Use "test-server [command] --help" for more information about a command.

[Annhiluc]

Wondering, how was this tested/verified?

[Annhiluc]

Update to latest?

[wanlin31]

Wondering, how was this tested/verified?

Thank you for helping me take a look at the PR, updated in the PR description.
The results only shows that the binary is executable, I have tried e2e for in github.com//pull/34 with a sample like what typescript did.